Skeletal SystemChapter 16 (pages 301-310)

Bones Living tissue (hard

form of connective tissue)

Chief supporting tissue of body

Provide: PROTECTION for vital

structures SUPPORT for body Mechanical basis for

MOVEMENT STOREHOUSE for

minerals Continuous supply of

new blood cells (PRODUCTION)

Skeleton Total 206 bones

Babies born with 270 soft bones; by adulthood these 64 bones will have fused together into hard, permanent bones.

Bone AnatomyTypes Flat Irregular Short Long

Structures Diaphysis Epiphysis Articular cartilage Periosteum Medullary cavity

Types of Bone Flat

Thin, flattened, and usually a bit curved

Serve protective function Scapula, sternum, ribs, most

bones of skull

Irregular Have weird shapes that do

not fit other 3 classes Vertebrae, hip, 2 skull bones

(sphenoid, ethmoid bones)

Short Cube-like in shape Found in carpals (wrist) and

tarsals (ankle)

Long Much longer than they are

wide All bones of limbs (except

patella, carpals, tarsals) Consists of shaft plus 2

expanded ends

Types of Bone

Structure of a Long Bone Diaphysis: shaft of long

bone Epiphysis: end of a long

bone Articular Cartilage: covers

bearing surface of bone Periosteum: fibrous tissue

that covers the bone Medullary Canal: center of

the shaft

Bone Formation/Growth Osteocyte: bone cell Ossification: the process of bone formation Bones grow in length and ossify from the

center of the diaphysis toward the epiphyseal extremities

Osteoblast: bone cells that build bone Osteoclast: bone cells that reabsorb bone

Axial Skeleton 80 bones Bones of:

Head (skull) Neck (spine) Trunk (sternum, ribs)

Spinal Column Cervical Thoracic Lumbar Sacrum Coccyx

Appendicular Skeleton 126 bones Bones of:

Pelvis Shoulder girdles Limbs

Skull

Skull

Shoulder

Chest

Sternum

Ribs

Arm

Hand

Upper Extremity

ClavicleScapulaSternumRibsHumerusRadiusUlnaCarpalsMetacarpalsPhalanges

Spine/Pelvis

PelvisSacrumPubic Bone/ Pubis

Sacrum

Pubis

Os Coxa

Leg

Foot

Tarsals

Lower Extremity

Skeletal Injuries—Fracture Fractures (fx): break in

bone Failure point: amount of

energy needed to cause a fracture

Simple (closed) Compound (open)

Direct trauma Fx directly at site

where force applied Indirect trauma

Fx occurs some distance where force applied

Sudden, violent muscle ctx or repetitive abnormal stress to bone

Simple (Closed) Fracture

Occurs when forces on bone exceed the bone’s ability to withstand forces applied

May be complete or incomplete

Compound (Open) Fracture Complete break in bone where bone ends separate

and break through skin Increased chance of wound and bone infection

Acute Bone Fractures Depressed Greenstick Impacted Longitudinal Spiral Oblique

Serrated Transverse Comminuted Contrecoup Blowout Avulsion

Depressed Fracture Most often in flat bones (skull) Caused by falling & striking head on hard,

immovable surface Hit with hard object Result in gross

pathology of soft areas

Greenstick Fracture Incomplete break in the

shaft of bone Occurs in children b/c

bones more pliable Usually occurs on

outer bend Direct blow

Impacted Fracture Long bone receives such force that osseous

tissue compressed Fall from height (compression) Require immediate splinting by ATC and

traction by physician to ensure normal length of injured limb

Longitudinal Fracture Bone splits along its

length Athlete jumping form

height and landing in way as to impact force or stress to long axis (compression)

Spiral Fracture S-shaped separation Common football or

skiing Foot firmly planted

when body suddenly rotated in opposing direction (torsion)

Oblique Fracture Similar to spiral Occur when one end of

bone receives sudden torsion or twisting while other end fixed or stabilized (torsion)

Serrated Fracture Two bony fragments have a sawtooth, sharp-

edged fx line Usually caused by direct blow Can cause extensive internal damage

Severance of vital blood vessels and nerves

Transverse Fracture Occur in straight line,

more or less at right angles to bone shaft

Direct outside blow

Comminuted Fracture Break in bone in which

bone shattered in many pieces (3+)

Hard blow or fall in awkward position

Contrecoup Occur on opposite side

to point at which trauma initiated

Blowout Fracture Occur to wall of the

eye orbit as result of a blow to the eye

Avulsion Fracture Separation of bone fragment from cortex at an

attachment of a ligament or tendon Sudden, powerful twist or stretch of

body part

Stress Fracture Small incomplete break

in bone due to: Overuse Poor muscle balance Lack of flexibility Weakness in soft tissue Biomechanical

problems Malnutrition

Stresses on body are greater than body can compensate

Symptoms Pain Tenderness after

activity No or little pain in

AM, but pain returns after activity

Epiphyseal Plate Fracture Break in bone at growth plate Most in individuals (age 10-16) due to sports participation X-ray won’t show fx of epiphyseal b/c epiphyseal plate

shows up clear

Fractures Signs & Symptoms

Swelling (edema) Deformity Pain Tenderness Discoloration Loss of function

Treatment Internal fixation External fixation Remodeling: process of

absorbing and replacing bone

Treatment & Repair Internal Fixation Surgery required to

align bones and reduce fracture

External Fixation Use of cast to keep

bones aligned while natural healing occurs

Skeletal InjuriesSubluxation Occurs when bone

displaces, then returns to normal position

Dislocation Occurs when

significant force displaces bone so that the two bone ends in a joint no longer add up